> Not sure what advantages an imessage vs sms groupchat even give me in this era of unlimited texting. Pretty hearts?

Some cellular carriers still charge per MMS message, so group chats (which use MMS) can get expensive. MMS group messages also have some undesirable properties -- in particular, adding or removing users from a group is unreliable, because each device is responsible for generating a list of recipients itself.

Plus, iMessage uses end-to-end encryption. MMS does not.